As an exclusively breastfeeding and working mom, I'd say it's not necessary unless LDR kayo ni baby at hindi ka daily nakakauwi and/ or hindi talaga kasya sa existing ref/ freezer nyo.
You really don't need a huge stash, specially kung uwian ka rin naman at makaka-unlilatch na si baby after your work ☺️ Baby only needs to consume 1.0 - 1.5oz/ hr na hindi kayo magkasama, basta unlilatch lang pag-uwi mo ng bahay. And having a stash that's good enough for 2-3days is more than enough. Basta make sure to pump every 2-3hs while away kay baby.
I'm assuming na working ka but if you're a full-time mom, then that's even more reason why it's unnecessary ☺️